STONE AND WOOD BORERS 351 



through the whole length of it, and the entire set of 

 twenty-seven volumes lifted up at once by it. 



There are one or two other grubs which less com- 

 monly injure books, and pass as " book-worms." But the 

 most notable of the insect enemies of books and papers 

 is a curious little wingless insect which never passes 

 through a grub stage of existence, but hatches out in the 

 complete form of his parents. He is about a third of an 

 inch long, has the shape of an elongated kite, with a long 

 tail and six legs, and is called by old writers " the silver- 

 fish," and by entomologists Lepisma (Fig. 63). This little 

 pest does not burrow, but nibbles, and has destroyed 

 many a valuable old document and ancient book. Paste 

 and sugar are a great attraction to him, and he will 

 destroy a boxful of printed labels or a valuable manu- 

 script, leaving only the ink-marked parts untouched, but 

 ready to crumble. 



Closely allied to the book-worm beetle, Anobium, is 

 a larger beetle, called Xestobium tessellatum (Fig. 620) 

 which infests old woodwork, its grubs making corre- 

 spondingly larger tunnels. The entire woodwork of a 

 house has had to be removed and replaced in conse- 

 quence of this creature's depredation, and such pieces of 

 furniture as a four-post bedstead have been riddled and 

 made rotten in two or three years by its burrowing. It 

 is still common in England in old wood-panelled rooms 

 and in wooden mantelpieces. The most interesting fact 

 about it is that it is the maker of those nocturnal tappings 

 which are known as the " death-watcli." It is the beetle 

 itself (Fig. 62 a), not the grub, which makes these sounds. 

 It makes them by deliberately striking the wood on which 

 it stands, with its head. The taps are usually from five 

 to seven in quick succession, the sound dying away in 

 intensity in the later strokes. A second, and even a third, 

 beetle will then reply with similar taps from the woodwork 



